<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
namespace Think\Cache\Driver;

use Think\Cache;

defined ( 'THINK_PATH' ) or exit ();
/**
 * Memcache缓存驱动
 * 
 * @category Extend
 * @package Extend
 * @subpackage Driver.Cache
 * @author liu21st <liu21st@gmail.com>
 */
class Memcachesae extends Cache {
	
	/**
	 * 架构函数
	 * 
	 * @param array $options
	 *        	缓存参数
	 * @access public
	 */
	function __construct($options = array()) {
		if (empty ( $options )) {
			$options = array (
					'host' => C ( 'MEMCACHE_HOST' ) ? C ( 'MEMCACHE_HOST' ) : '127.0.0.1',
					'port' => C ( 'MEMCACHE_PORT' ) ? C ( 'MEMCACHE_PORT' ) : 11211,
					'timeout' => C ( 'DATA_CACHE_TIMEOUT' ) ? C ( 'DATA_CACHE_TIMEOUT' ) : false,
					'persistent' => false 
			);
		}
		$this->options = $options;
		$this->options ['expire'] = isset ( $options ['expire'] ) ? $options ['expire'] : C ( 'DATA_CACHE_TIME' );
		$this->options ['prefix'] = isset ( $options ['prefix'] ) ? $options ['prefix'] : C ( 'DATA_CACHE_PREFIX' );
		$this->options ['length'] = isset ( $options ['length'] ) ? $options ['length'] : 0;
		// $func = isset($options['persistent']) ? 'pconnect' : 'connect';
		$this->handler = memcache_init (); // [sae] 下实例化
		                                        // [sae] 下不用链接
		$this->connected = true;
		// $this->connected = $options['timeout'] === false ?
		// $this->handler->$func($options['host'], $options['port']) :
		// $this->handler->$func($options['host'], $options['port'], $options['timeout']);
	}
	
	/**
	 * 是否连接
	 * 
	 * @access private
	 * @return boolean
	 */
	private function isConnected() {
		return $this->connected;
	}
	
	/**
	 * 读取缓存
	 * 
	 * @access public
	 * @param string $name
	 *        	缓存变量名
	 * @return mixed
	 */
	public function get($name) {
		N ( 'cache_read', 1 );
		return $this->handler->get ( $_SERVER ['HTTP_APPVERSION'] . '/' . $this->options ['prefix'] . $name );
	}
	
	/**
	 * 写入缓存
	 * 
	 * @access public
	 * @param string $name
	 *        	缓存变量名
	 * @param mixed $value
	 *        	存储数据
	 * @param integer $expire
	 *        	有效时间（秒）
	 * @return boolean
	 */
	public function set($name, $value, $expire = null) {
		N ( 'cache_write', 1 );
		if (is_null ( $expire )) {
			$expire = $this->options ['expire'];
		}
		$name = $this->options ['prefix'] . $name;
		if ($this->handler->set ( $_SERVER ['HTTP_APPVERSION'] . '/' . $name, $value, 0, $expire )) {
			if ($this->options ['length'] > 0) {
				// 记录缓存队列
				$this->queue ( $name );
			}
			return true;
		}
		return false;
	}
	
	/**
	 * 删除缓存
	 * 
	 * @access public
	 * @param string $name
	 *        	缓存变量名
	 * @return boolean
	 */
	public function rm($name, $ttl = false) {
		$name = $_SERVER ['HTTP_APPVERSION'] . '/' . $this->options ['prefix'] . $name;
		return $ttl === false ? $this->handler->delete ( $name ) : $this->handler->delete ( $name, $ttl );
	}
	
	/**
	 * 清除缓存
	 * 
	 * @access public
	 * @return boolean
	 */
	public function clear() {
		return $this->handler->flush ();
	}
	
	/**
	 * 队列缓存
	 * 
	 * @access protected
	 * @param string $key
	 *        	队列名
	 * @return mixed
	 */
	// [sae] 下重写queque队列缓存方法
	protected function queue($key) {
		$queue_name = isset ( $this->options ['queue_name'] ) ? $this->options ['queue_name'] : 'think_queue';
		$value = F ( $queue_name );
		if (! $value) {
			$value = array ();
		}
		// 进列
		if (false === array_search ( $key, $value ))
			array_push ( $value, $key );
		if (count ( $value ) > $this->options ['length']) {
			// 出列
			$key = array_shift ( $value );
			// 删除缓存
			$this->rm ( $key );
			if (APP_DEBUG) {
				// 调试模式下记录出队次数
				$counter = Think::instance ( 'SaeCounter' );
				if ($counter->exists ( $queue_name . '_out_times' ))
					$counter->incr ( $queue_name . '_out_times' );
				else
					$counter->create ( $queue_name . '_out_times', 1 );
			}
		}
		return F ( $queue_name, $value );
	}
}
